Round 1: Cast two action spell, get four actions out of it. (Two per body, one of which has to be a stride on each body).
Round 2+: Sustain (takes an action unless you have some other ability to free sustain), both bodies "share actions" (of which you generally have two left), until 8th rank, when you're quickened and effectively have three useable actions across your two bodies.
It's the old PF1, PF2, SF1 Bilocation spell but as a focus spell. It was a very bad spell of waaaay too high a rank in those systems, it's not great here but not actively a trap anymore.
For just the first round cast you can move into flanking position and get two full MAP attacks (albeit against different targets), which is quite good. Or you can move into flanking, attack, demoralize or some other skill action or one action spell, and still have another action free.
On subsequent rounds you're in flanking (until they move), or you're using it out of combat for something goofy like showing one body at the dinner party you just entered while the other is sneaking upstairs or whatever. (The traditional waste of an 8th/9th rank Bilocation that was otherwise totally useless in combat.)